1. Field of the Invention
The present invention relates to an image processing apparatus that may be applied to a car navigation apparatus, for example, a distant view image display method, and a distant view image display program.
2. Description of the Related Art
A car navigation apparatus that displays the current position and/or the traveling direction of a subject vehicle on a map displayed on a display screen is becoming popular, and with the dramatic advancement of depiction technology, there is a growing demand for the adoption of a 3D (three-dimensional) map as the map for car navigation. It is noted that a 3D map for car navigation is configured to display roads as the main object along with 3D images of buildings.
It is noted that a map for car navigation is configured to depict a view of an area within a certain distance range from a subject vehicle, and in recent years and continuing, depicting a view from a high viewpoint to display a wide map area is becoming the mainstream display technique for car navigation. In this case, an upper portion of the display screen where the depiction of the map area ends is generally represented as a horizon. In most cases, a specific image for a depiction area extending beyond such a horizon is not provided, and a general image of the sky is often depicted in such a depiction area. It is noted that Japanese Laid-Open Patent Publication No. 2001-83872 discloses a technique relating to displaying a distant view image including mountains, clouds, and the sky, for example, at the upper side of the horizon. However, the specific mechanisms for realizing such a technique are not disclosed in the above document.
As can be appreciated, in a conventional car navigation apparatus, special considerations have not been made with regard to the depiction area extending beyond the horizon. However, with the adaptation of the 3D map, buildings are being represented in a more realistic manner, and in turn there is a growing demand for improvement in the quality of the background image being depicted in order to maintain a balance with the depicted buildings.
In this regard, a fixed distant view image of mountains, for example, may be prepared beforehand and depicted at the portion beyond the horizon. However, in this case, mountains may always be depicted even when an area that is not surrounded by mountains is displayed such as an area along the sea. This may create awkwardness in the displayed image. On the other hand, if a database of distant view images for every location were prepared and arranged to be reproduced accordingly, processing and operations may be burdensome. Moreover, such accurate distant views in car navigation are not necessary.